The present invention relates generally to medical devices and more particularly to a wireguide and catheter for changing access to a treatment site from two different access sites.
Minimally invasive medical procedures have become common in the medical profession due to the lower risk and trauma associated with minimally invasive procedures and the lower cost compared to open surgical procedures. Minimally invasive procedures generally involve gaining access to a patient's internal vessel by puncturing the patient's skin, intermediate tissues between the skin and the vessel, and the wall of the vessel. An elongate medical instrument may then be inserted through the access site so that the distal end of the medical instrument is located within the patient's internal vessel, while the proximal end of the medical instrument remains outside the patient's body. The physician may then manipulate the proximal end of the medical instrument outside the patient's body to move and orient the distal end of the medical instrument to a location within the vessel where treatment is needed. Thus, a treatment site within a patient's vessel may be treated from outside the patient's body through a relatively small access site that is located some distance from the treatment site. By contrast, conventional open surgical procedures would require opening the tissues immediately adjacent the treatment site so that the surgeon can gain direct access to the treatment site.
One example of where minimally invasive procedures are commonly used is the treatment of stenoses and other obstructions within vessels using angioplasty techniques. Typically, angioplasty procedures are performed using a balloon-tipped catheter that may or may not have a balloon-expandable stent mounted on the balloon. In general, a physician performs an angioplasty procedure by introducing a balloon catheter into a peripheral artery (commonly one of the leg or arm arteries) and threading the catheter to the narrowed region of the artery. During this stage, the balloon is uninflated and collapsed onto the shaft of the catheter in order to present a low profile which may be passed through the arterial lumens. Once the balloon is positioned at the narrowed region of the artery, the balloon is expanded by pumping a mixture of saline and contrast solution through the catheter to the balloon. As a result, the balloon presses against the inner wall of the artery to dilate it. If a balloon-expandable stent is mounted on the balloon, the balloon inflation also serves to expand the stent and implant it in the artery. After the artery is dilated, the balloon is deflated so that it once again collapses onto the shaft of the catheter. The balloon-tipped catheter is then retracted from the arteries. If a stent is mounted on the balloon of the catheter, the stent is left permanently implanted in its expanded state at the desired location in the artery to provide a support structure that prevents the artery from collapsing back to its pre-dilated condition. Alternatively, the balloon catheter may be used to dilate a stenosis without implanting a stent. A balloon-expandable stent or self-expandable stent may then be implanted in the dilated region in a follow-up procedure. If desired, a physician may also dilate the artery and stent a second time after the stent is implanted with a balloon catheter.
In most minimally invasive procedures, a single access site is sufficient to treat a particular condition within a vessel. Although multiple medical instruments may be needed to complete the entire procedure (e.g., angiography catheter, filter, balloon catheter, a stent delivery system, etc.), each of the medical instruments usually access the treatment site through a single access site. Thus, an operation requiring multiple medical instruments can be performed with a single access site by alternately withdrawing and inserting each of the instruments through the access site. This is a significant advantage of minimally invasive procedures because complicated medical procedures involving numerous different instruments can be accomplished while limiting trauma to a single, relatively small access site.
Although most minimally invasive medical procedures use a single access site to minimize trauma and cost, some minimally invasive medical procedures may benefit from the use of two different access sites, where the two access sites are on opposite sides of the treatment site. However, obtaining access to the treatment site from two different access sites can be complicated and time-consuming. Therefore, the inventor believes an improved wireguide set for changing access between two different access sites would be desirable.